Optoelectronics and CMOS integration on GOI substrate

ABSTRACT

A single chip including an optoelectronic device on the semiconductor layer in a first region, the optoelectronic device comprises a bottom cladding layer, an active region, and a top cladding layer, wherein the bottom cladding layer is above and in direct contact with the semiconductor layer, the active region is above and in direct contact with the bottom cladding layer, and the top cladding layer is above and in direct contact with the active region, a silicon device on the substrate extension layer in a second region, a device insulator layer substantially covering both the optoelectronic device in the first region and the silicon device in the second region, and a waveguide embedded within the device insulator layer in direct contact with a sidewall of the active region of the optoelectronic device.

BACKGROUND

The present invention generally relates to semiconductor devicemanufacturing, and more particularly to the formation and integration ofa III-V semiconductor optoelectronic device and a silicon complementarymetal-oxide-semiconductor (CMOS) device on a single chip.

As micro-electronic systems continue to scale down, the resultantelectrical interconnect density would have to accommodate increasedpower dissipation, signal delay and cross-talk, while running atextremely high clock speeds. Current trends indicate that in less than adecade the power consumed by interconnects might become the limitingfactor in determining the switching speeds in integrated circuits. Toovercome these problems the integration of optical interconnects andsystems alongside conventional Silicon (Si) based micro-electroniccircuits would be a major step forward. Light based intra and inter-chipcommunication would diminish latency considerably and reduce powerconsumption by eliminating capacitive interconnect loss. Improvedopto-electronic integration can also help increase the speed oftransceiver circuits used in optical communication systems, therebyincreasing the overall bandwidth.

SUMMARY

According to one embodiment of the present invention, a method isprovided. The method may include forming a semiconductor-on-insulator(SOI) substrate in a first region and a second region, the SOI substrateincludes a semiconductor layer on a first insulator layer, and the firstinsulator layer is on a substrate; removing the semiconductor layer andthe insulator layer from the second region, wherein a top surface of thesubstrate is exposed; forming a second insulator layer on thesemiconductor layer in the first region; forming a substrate extensionlayer on the exposed substrate in the second region; forming the deviceon the substrate extension layer; forming a device insulator layercovering the device in the second region; forming a waveguide in thesecond insulator layer; and forming the optoelectronic device in thefirst region, the optoelectronic device has a bottom cladding layer, anactive region, and a top cladding layer, wherein the bottom claddinglayer is on the semiconductor layer, the active region is on the bottomcladding layer, and the top cladding layer is on the active region.

According to another embodiment of the present invention, a method isprovided. The method may include forming a stack of layers on asubstrate in a first region and in a second region, the stack of layersinclude a semiconductor layer on the substrate, a first insulator layeron the semiconductor layer, a waveguide on the first insulator layer, asecond insulator layer on the waveguide, and a device base layer on thesecond insulator layer; forming the device on the device base layer inthe second region; forming a device insulator layer on the device and onthe device base layer in the second region; and forming theoptoelectronic device in the first region, the optoelectronic device hasa bottom cladding layer, an active region, and a top cladding layer,wherein the bottom cladding layer is on the semiconductor layer, theactive region is on the bottom cladding layer, and the top claddinglayer is on the active region.

According to another embodiment of the present invention, a structure isprovided. The structure may include a silicon substrate in a firstregion and a second region of a single chip; a germanium layer above thesubstrate in at least the first region; the optoelectronic device on thegermanium layer in the first region, the optoelectronic device has abottom cladding layer, an active region adjacent to a waveguide, and atop cladding layer, wherein the bottom cladding layer is on thegermanium layer, the active region is on the bottom cladding layer, andthe top cladding layer is on the active region; and the silicon deviceon a silicon layer in the second region.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and notintended to limit the invention solely thereto, will best be appreciatedin conjunction with the accompanying drawings, in which:

FIG. 1 is a cross section view of a semiconductor structure, accordingto an exemplary embodiment;

FIG. 2 is a cross section view of the semiconductor structure andillustrates the removal of a semiconductor layer and first insulatorlayer from a first region of a semiconductor-on-insulator (SOI)substrate, according to an exemplary embodiment;

FIG. 3 is a cross section view of the semiconductor structure andillustrates the formation of a device in a second region of the SOIsubstrate, according to an exemplary embodiment;

FIG. 4 is a cross section view of the semiconductor structure andillustrates the formation of a waveguide above the semiconductor layerin the first region, according to an exemplary embodiment;

FIG. 5 is a cross section view of the semiconductor structure andillustrates the formation of an optoelectronic device in the firstregion, according to an exemplary embodiment;

FIG. 6 is a cross section view of the semiconductor structure andillustrates the formation of an optoelectronic device contact and adevice contact, according to an exemplary embodiment;

FIG. 7 is a cross section view of the semiconductor structure andillustrates a top view of the semiconductor structure, according to anexemplary embodiment;

FIG. 8 is a cross section view of an alternative semiconductor structureand illustrates the formation of a stack of layers on a substrate,according to an exemplary embodiment;

FIG. 9 is a cross section view of the alternative semiconductorstructure and illustrates the formation of a device in a second regionof an SOI substrate, according to an exemplary embodiment; and

FIG. 10 is a cross section view of the alternative semiconductorstructure and illustrates the formation of an optoelectronic device in afirst region of the SOI substrate, according to an exemplary embodiment.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention. In the drawings, like numbering representslike elements.

DETAILED DESCRIPTION

Detailed embodiments of the claimed structures and methods are disclosedherein; however, it can be understood that the disclosed embodiments aremerely illustrative of the claimed structures and methods that may beembodied in various forms. This invention may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the scope of this invention to thoseskilled in the art. In the description, details of well-known featuresand techniques may be omitted to avoid unnecessarily obscuring thepresented embodiments.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the disclosed structures andmethods, as oriented in the drawing figures. The terms “overlying”,“atop”, “on top”, “positioned on” or “positioned atop” mean that a firstelement, such as a first structure, is present on a second element, suchas a second structure, wherein intervening elements, such as aninterface structure may be present between the first element and thesecond element. The term “direct contact” means that a first element,such as a first structure, and a second element, such as a secondstructure, are connected without any intermediary conducting, insulatingor semiconductor layers at the interface of the two elements.

In the interest of not obscuring the presentation of embodiments of thepresent invention, in the following detailed description, someprocessing steps or operations that are known in the art may have beencombined together for presentation and for illustration purposes and insome instances may have not been described in detail. In otherinstances, some processing steps or operations that are known in the artmay not be described at all. It should be understood that the followingdescription is rather focused on the distinctive features or elements ofvarious embodiments of the present invention.

The present invention generally relates to semiconductor devicemanufacturing, and more particularly to the formation and integration ofa III-V semiconductor optoelectronic device and a silicon complementarymetal-oxide-semiconductor (CMOS) device on a single chip. Ideally, itmay be desirable to form a III-V semiconductor optoelectronic device anda silicon CMOS device on the same chip to create new pathways foroptical interconnects and to reduce production time and cost. One way tofabricate a III-V semiconductor optoelectronic device and a silicon CMOSdevice on a single chip may include forming a silicon substrate in afirst and second region on a single chip, forming a germanium layer inthe first region, using the germanium layer as a seed layer to form aIII-V semiconductor optoelectronic device, and using the silicon in thesecond region as a seed layer to form a silicon CMOS device. Oneembodiment by which to form an integrated III-V semiconductoroptoelectronic device and a silicon CMOS device on the same chip isdescribed in detail below referring to the accompanying drawings FIGS.1-10. It should be noted, an optoelectronic device may include, forexample, an optoelectronic transmitting device, such as a laser, or anoptoelectronic receiving device, such as a detector, but other devicesmay be used.

With reference to FIG. 1, a demonstrative illustration of a structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan start with providing a semiconductor-on-insulator (SOI) substrate.

The SOI substrate may be in a first region 101 and in a second region103 of a single chip. The SOI substrate may include (from bottom to top)a substrate 102, a first insulator layer 104, and a semiconductor layer106. The SOI substrate may be formed using any SOI substrate formationtechnique known in the art, such as, for example, Separation by IonImplantation of Oxygen (SIMOX) or layer transfer. If a layer transferprocess is employed, an optional thinning step may follow the bonding oftwo semiconductor wafers together. The optional thinning step can reducethe thickness of a layer to a desirable thickness.

The substrate 102 may include; a bulk semiconductor substrate, a layeredsemiconductor substrate (e.g., Si/SiGe), a silicon-on-insulatorsubstrate (SOI), or a SiGe-on-insulator substrate (SGOI). The substrate102 may include any semiconductor material known in the art, such as,for example; Si, Ge, SiGe, SiC, SiGeC, Ga, GaAs, InAs, InP, or otherelemental or compound semiconductors. In an embodiment, the substrate102 is a bulk silicon substrate. The substrate 102 may include, forexample; an n-type, p-type, or undoped semiconductor material and mayhave a monocrystalline, polycrystalline, or amorphous structure.

The first insulator layer 104 may be formed on the substrate 102 usingany deposition techniques known in the art, such as, for example; ionimplantation, thermal or plasma oxidation or nitridation, chemical vapordeposition, and/or physical vapor deposition. The first insulator layer104 may be any dielectric material known in the art, such as, forexample; oxides, nitrides, or oxynitrides. The first insulator layer 104may have a thickness ranging from about 1 nm to about 500 nm, but otherthicknesses may be used. In an embodiment, the first insulator layer 104is SiO₂ having a thickness of about 200 nm. In another embodiment, thefirst insulator layer 104 may include multiple dielectric layers or astack of dielectric layers including a silicon oxide layer and/or asilicon nitride layer. It should be noted; the first insulator layer 104may also be referred to as a buried dielectric layer or a buried oxide(BOX) layer.

The semiconductor layer 106 may be formed on the first insulator layer104 using any deposition technique known in the art, such as, forexample, chemical vapor deposition, plasma enhanced chemical vapordeposition, atomic layer deposition, or physical vapor deposition. Thesemiconductor layer 106 may be any semiconductor material known in theart, such as, for example, Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP orother semiconductors. The semiconductor layer 106 may have a thicknessranging from about 1 nm to about 500 nm, but other thicknesses may beused. In an embodiment, the semiconductor layer 106 is germanium and hasa thickness of about 100 nm.

In an embodiment, a III-V semiconductor layer may be subsequently formedon the semiconductor layer 106 (further described below). The latticemismatch is larger between silicon and a III-V semiconductor thanbetween germanium and the III-V semiconductor; therefore, germanium maybe a better material to use as the semiconductor layer 106 for thesubsequent formation of a III-V semiconductor optoelectronic device.

With reference to FIG. 2, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include removing the semiconductor layer 106 and the first insulatorlayer 104 from the second region 103 and forming a second insulatorlayer 108 on the semiconductor layer 106.

It should be noted, germanium may be a good material for the growth of aIII-V semiconductor optoelectronic device; however, silicon may bebetter suited for the formation of other devices, such as, for example,a CMOS device. Therefore, the germanium may be removed from the secondregion 103 to allow for subsequent formation of silicon devices.

The semiconductor layer 106 and the first insulator layer 104 may beremoved from the second region 103 using any etching technique known inthe art, such as, for example, photolithography and/or reactive ionetching process. A top surface of the substrate 102 may be exposed inthe second region 103.

The second insulator layer 108 may be formed on the semiconductor layer106 using any deposition technique known in the art, such as, forexample, chemical vapor deposition, plasma enhanced chemical vapordeposition, atomic layer deposition, or physical vapor deposition. In anembodiment, the second insulator layer 108 is formed on thesemiconductor layer 106 by depositing a blanket insulator layer over thesemiconductor layer 106 in the first region 101 and the substrate 102 inthe second region 103 followed by an etching process removing theblanket insulator layer from the second region 103. The second insulatorlayer 108 may remain on the semiconductor layer 106 and on sidewalls ofthe semiconductor layer 106 and first insulator layer 104 adjacent tothe second region 103. The second insulator layer 108 may be anydielectric material known in the art, such as, for example, oxides,nitrides, or oxynitrides. The second insulator layer 108 may have athickness ranging from about 1 μm to about 5 μm, but other thicknessesmay be used. In an embodiment, the second insulator layer 108 is thesame material as the first insulator layer (e.g., SiO₂) and has athickness of about 2 μm above the semiconductor layer 106.

With reference to FIG. 3, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming a device 112 on a substrate extension layer 110 inthe second region 103.

The substrate extension layer 110 may be formed on the substrate 102 inthe second region 103 using any deposition technique known in the art,such as, for example, epitaxial growth, chemical vapor deposition,plasma enhanced chemical vapor deposition, atomic layer deposition, orphysical vapor deposition. The substrate extension layer 110 may be anysemiconductor material known in the art, such as, for example, Si, Ge,SiGe, SiC, SiGeC, InAs, GaAs, InP or other semiconductors. In anembodiment, the substrate extension layer 110 is the same material asthe substrate 102 (e.g., Si) and the substrate extension layer 110 isgrown on the exposed substrate 102 in the second region 103 using anepitaxial growth process.

The device 112 may be formed on the substrate extension layer 110 usingany device formation technique known in the art, such as, for example, adeposition, masking, and etching process. The device 112 may be anyelectrical device known in the art, such as, for example, a Si CMOSdevice, SiGe or III-V channel MOSFETs, bipolar junction transistors, orany other devices used in the art. In an embodiment, the device 112 is aSi CMOS device. The device 112 may be used to send signals to a laser ordetector, as is known in the art. In the illustrated embodiment, twosets of three devices 112 are formed on the substrate extension layer110; however, other device configurations may be used.

A device insulator layer 109 may be formed on the device 112 using anydeposition technique known in the art, such as, for example, chemicalvapor deposition, plasma enhanced chemical vapor deposition, atomiclayer deposition, or physical vapor deposition. The device insulatorlayer 109 may be any dielectric material known in the art, such as, forexample, oxides, nitrides, or oxynitrides. In an embodiment, the deviceinsulator layer 109 is the same material as the first and secondinsulator layers 104, 108 (e.g., SiO₂). A top surface of the secondinsulator layer 108 and the device insulator layer 109 may be planarizedusing any polishing technique known in the art, such as, for example, achemical-mechanical polishing process.

With reference to FIG. 4, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming a waveguide 114 in the first region 101.

The waveguide 114 may be formed in the first region 101 by etching atrench in the second insulator layer 108, forming the waveguide 114 inthe trench, and reforming the second insulator layer 108 above thewaveguide 114. The trench may be formed in the second insulator layer108 using any etching technique known in the art, such as, for example,a reactive ion etching process. A portion of the second insulator layer108 may remain underneath the trench. The portion of the secondinsulator layer 108 remaining underneath the trench may have a thicknessof about 1 μm. The trench may not extent to the second region 103 (i.e.,there may be a portion of the second insulator layer 108 between thetrench and the second region 103).

The waveguide 114 may be deposited in the trench using any depositiontechnique known in the art, such as, for example, chemical vapordeposition, plasma enhanced chemical vapor deposition, atomic layerdeposition, or physical vapor deposition. The waveguide 114 may be anywaveguide material known in the art, such as, for example, nitrides,oxides, or oxynitrides. In an embodiment, the waveguide 114 is SiN.

The second insulator layer 108 may be reformed on the waveguide 114using any deposition technique known in the art, such as, for example,chemical vapor deposition, plasma enhanced chemical vapor deposition,atomic layer deposition, or physical vapor deposition. The top surfaceof the second insulator layer 108 may be planarized using any polishingtechnique known in the art, such as, for example, a chemical-mechanicalpolishing process. In an embodiment, the second insulator layer 108 hasa thickness of about 1 μm above a top surface of the waveguide 114.

With reference to FIG. 5, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming an optoelectronic device 115 on the semiconductorlayer 106 in the first region 101.

Various types of structures have been advocated for semiconductor lasersand detectors; one typical structure is the double hetero structure. Thedouble hetero structure is a structure such that, using two types ofdifferent compound semiconductors, the compound semiconductor with asmaller bandgap is sandwiched between the compound semiconductors withlarger bandgaps.

The optoelectronic device 115 may include (from bottom to top) a bottomcladding layer 116, an active region 118, and a top cladding layer 117(e.g., a double hetero structure). The optoelectronic device 115 mayhave a width (w) ranging from about 1 μm to about 10 μm and a lengthranging from about 100 μm to about 500 μm, but other dimensions may beused.

The optoelectronic device 115 may be formed by etching a trench in thesecond insulator layer 108 using any etching technique known in the art,such as, for example, a photolithography and/or reactive ion etchingprocess. The trench may be formed in the first region 101 and may exposea top surface of the semiconductor layer 106 and a sidewall of thewaveguide 114.

The bottom cladding layer 116 may be formed in the trench and on thesemiconductor layer 106 using any deposition technique known in the art,such as, for example, epitaxial growth or chemical vapor deposition. Thebottom cladding layer 116 may include any semiconductor material knownin the art, such as, for example, IV semiconductors and/or III-Vsemiconductors. In an embodiment, the bottom cladding layer 116 isAlGaAs. The bottom cladding layer 116 may be doped in-situ and may bep-type or n-type.

The active region 118 may be formed on the bottom cladding layer 116using any deposition technique known in the art, such as, for example,epitaxial growth or chemical vapor deposition. The active region 118 mayinclude any semiconductor material known in the art, such as, forexample, IV semiconductors and/or III-V semiconductors. In anembodiment, the active region 118 is GaAs formed using epitaxial growth.The active region 118 may have the same lattice structure as the bottomcladding layer 116, however, the active region 118 may have a lowerbandgap. The active region 118 may be in contact with the sidewall ofthe waveguide 114, such that signals can flow between the active region118 and the waveguide 114.

The top cladding layer 117 may be formed on the active region 118 usingany deposition technique known in the art, such as, for example,epitaxial growth or chemical vapor deposition. The top cladding layer117 may include any semiconductor material known in the art, such as,for example, IV semiconductors and/or III-V semiconductors. The topcladding layer 117 may be doped in-situ and may be p-type or n-type. Inan embodiment, the top cladding layer 117 is the same material as thebottom cladding layer 116 (e.g., AlGaAs) and may have an opposite chargefrom the bottom cladding layer 116 (e.g., a p-type top cladding layer117 and an n-type bottom cladding layer 116). The top and bottomcladding layers 117, 116 may be used as a barrier layer which mayconfine electrons in the active region 118.

With reference to FIG. 6, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming an optoelectronic device contact 122 and a devicecontact 124 through a top insulator layer. It should be noted, forillustrative purposes, the first insulator layer 104, the secondinsulator layer 108, the device insulator layer 109 and the topinsulator layer may be shown as a combined insulator 111.

The top insulator layer may be formed on the optoelectronic device 115,on the second insulator layer 108, and on the device insulator layer 109using any deposition techniques known in the art, such as, for example;ion implantation, thermal or plasma oxidation or nitridation, chemicalvapor deposition, and/or physical vapor deposition. The top insulatorlayer may be any dielectric material known in the art, such as, forexample; oxides, nitrides, or oxynitrides. In an embodiment, the topinsulator layer is the same material as the first insulator layer 104,the second insulator layer 108, and the device insulator layer 109(e.g., SiO₂).

An optoelectronic device contact trench and a device contact trench maybe etched in the combined insulator 111 using any etching techniqueknown in the art, such as, for example, a photolithography and/orreactive ion etching process. The optoelectronic device contact trenchmay include two trenches (e.g., a first trench and a second trench). Thefirst trench may extend through the combined insulator 111 and expose atop surface of the top cladding layer 116. A second trench may extendthrough the combined insulator 111 and expose a top surface of thebottom cladding layer 117. The device contact trench may include a setof trenches corresponding to the number of devices used. The devicecontact trench may extend through the combined insulator 111 and exposea top surface of the device 112.

The optoelectronic device contact 122 may be formed in theoptoelectronic device contact trench using any deposition techniqueknown in the art, such as, for example, atomic layer deposition,molecular layer deposition, chemical vapor deposition, in-situ radicalassisted deposition, metalorganic chemical vapor deposition, molecularbeam epitaxy, physical vapor deposition, sputtering, plating,evaporation, ion beam deposition, electron beam deposition, laserassisted deposition, chemical solution deposition, or any combinationthereof. The optoelectronic device contact 122 may be any conductivematerial known in the art, such as, for example, tungsten, aluminum,silver, gold, alloys thereof, or any other conductive material. A layerof silicide 113 may line the bottom of the optoelectronic device contact122.

The device contact 124 may be formed in the device contact trench usingany deposition technique known in the art, such as, for example, atomiclayer deposition, molecular layer deposition, chemical vapor deposition,in-situ radical assisted deposition, metalorganic chemical vapordeposition, molecular beam epitaxy, physical vapor deposition,sputtering, plating, evaporation, ion beam deposition, electron beamdeposition, laser assisted deposition, chemical solution deposition, orany combination thereof. The device contact 124 may be any conductivematerial known in the art, such as, for example, tungsten, aluminum,silver, gold, alloys thereof, or any other conductive material. A layerof silicide 119 may line the bottom of the device contact 124.

With reference to FIG. 7, a demonstrative illustration of the structure100 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, theoptoelectronic device 115 (described above) may include a set of lasers115 a and a set of detectors 115 b. The lasers 115 a may connect to thedetectors 115 b (i.e., intra-chip connections) or to separate detectors(i.e., inter-chip connections). In an embodiment, there are two firstregions 101, one region having the lasers 115 a and another having thedetectors 115 b, where the second region 103 is between the two firstregions 101. It should be noted, FIG. 7 is a top view of structure 100.Additionally, FIG. 7 is an exemplary illustration of a possibleconfiguration, but other configurations may be used.

With reference to FIG. 8, a demonstrative illustration of a structure200 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan start with a stack of layers including (from bottom to top) thesubstrate 102, a semiconductor layer 206, a first insulator layer 204, awaveguide 214, a second insulator 208, and a device base layer 210. Itshould be noted, structure 200 is exemplary of a waveguide-firstembodiment (rather than a device-first embodiment as illustrated inFIGS. 1-6).

The semiconductor layer 206 may be formed on the substrate 102. Thesemiconductor layer 206 may be a similar material, and formed using asimilar process, as the semiconductor layer 106 illustrated in FIG. 1.The first insulator layer 204 may be formed on the semiconductor layer206. The first insulator layer 204 may be a similar material, and formedusing a similar process, as the first insulator layer 104 illustrated inFIG. 1. The waveguide 214 may be formed on the first insulator layer104. The waveguide 214 may be a similar material, and formed using asimilar process, as the waveguide 114 illustrated in FIG. 4. The secondinsulator layer 208 may be formed on the waveguide 214. The secondinsulator 208 may be a similar material, and formed using a similarprocess, as the second insulator layer 108 illustrated in FIG. 2. Thedevice base layer 210 may be formed on the second insulator layer 208.The device base layer 210 may be a similar material, and formed using asimilar process, as the substrate extension layer 110 illustrated inFIG. 3.

The stack of layers may be in the first region 101 and in the secondregion 103. In an embodiment, the substrate 102 is silicon, thesemiconductor layer 206 is germanium, the first insulator layer 204 isSiO₂, the second insulator layer 208 is SiO₂, the waveguide 214 is SiN,and the device base layer 210 is silicon.

With reference to FIG. 9, a demonstrative illustration of the structure200 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming a device 212 on the device base layer 210 in thesecond region 103. The device 212 may be a similar material, and formedusing a similar process, as the device 112 illustrated in FIG. 3. Adevice insulator layer 209 may be formed on the device 212 and thedevice base layer 210. The device insulator layer 209 may be a similarmaterial, and formed using a similar process, as the device insulatorlayer 109 illustrated in FIG. 3.

With reference to FIG. 10, a demonstrative illustration of the structure200 is provided during an intermediate step of a method of fabricating aIII-V semiconductor optoelectronic device and a Si CMOS device on asingle chip, according to an embodiment. More specifically, the methodcan include forming an optoelectronic device 215 in the first region101.

The optoelectronic device 215 may be similar materials, and formed usinga similar process, as the optoelectronic device 115 illustrated in FIG.5. The optoelectronic device 215 may include a bottom cladding layer216, an active region 218, and a top cladding layer 217 formed in atrench on a top surface of the semiconductor layer 206. The structure200 may be similar to structure 100; however, the waveguide 214 mayextend underneath the device 212.

One benefit to having a laser/detector formed on the same chip as adevice may include quicker processing times and lower processing costs.Germanium may be used as the semiconductor seed layer for thelaser/detector because a closer lattice structure between germanium anda III-V semiconductor may result in less stress and/or misfitdislocations. The germanium may be grown on a silicon substrate or oxidesuch that the germanium can bridge the gap in lattice mismatch between asilicon substrate and a III-V semiconductor laser/detector.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

What is claimed is:
 1. A structure comprising: a germanium layer above asemiconductor substrate in a first region of the semiconductorsubstrate; an optoelectronic device on the germanium layer in the firstregion, the optoelectronic device has a bottom cladding layer, an activeregion adjacent to and contacting a waveguide, and a top cladding layer,wherein the bottom cladding layer is on the germanium layer, the activeregion is on the bottom cladding layer, and the top cladding layer is onthe active region; and a silicon device on a silicon layer in a secondregion of the semiconductor substrate, wherein an upper surface of thesilicon layer in the second region is above an upper surface of thegermanium layer in the first region.
 2. The structure according to claim1, wherein the optoelectronic device comprises a III-V semiconductormaterial.
 3. The structure according to claim 1, wherein the silicondevice is a silicon complementary metal-oxide-semiconductor (CMOS)device.
 4. The structure according to claim 1, further comprising: afirst contact, a second contact, and a device contact, wherein the firstcontact is directly connected to the top cladding layer, the secondcontact is directly connected to the bottom cladding layer, and thedevice contact is directly connected to the silicon device.
 5. Thestructure according to claim 1, wherein the waveguide is embedded in aninsulator layer and in direct contact with a sidewall of the activeregion of the optoelectronic device.
 6. The structure according to claim1, further comprising: an insulator layer substantially covering boththe optoelectronic device in the first region and the silicon device inthe second region.
 7. A structure comprising: a germanium layer above asemiconductor substrate in a first region of the semiconductorsubstrate; an optoelectronic device on the germanium layer in the firstregion, the optoelectronic device has a bottom cladding layer, an activeregion adjacent to and contacting a waveguide, and a top cladding layer,wherein the bottom cladding layer is on the germanium layer, the activeregion is on the bottom cladding layer, and the top cladding layer is onthe active region; and a silicon device on a silicon layer in a secondregion of the semiconductor substrate, wherein both the top claddinglayer and the bottom cladding layer are AlGaAs and the active region isGaAs.
 8. The structure according to claim 7, wherein the optoelectronicdevice comprises a III-V semiconductor material.
 9. The structureaccording to claim 7, wherein the silicon device is a siliconcomplementary metal-oxide-semiconductor (CMOS) device.
 10. The structureaccording to claim 7, further comprising: a first contact, a secondcontact, and a device contact, wherein the first contact is directlyconnected to the top cladding layer, the second contact is directlyconnected to the bottom cladding layer, and the device contact isdirectly connected to the silicon device.
 11. The structure according toclaim 7, wherein the waveguide is embedded in an insulator layer and indirect contact with a sidewall of the active region of theoptoelectronic device.
 12. The structure according to claim 7, furthercomprising: an insulator layer substantially covering both theoptoelectronic device in the first region and the silicon device in thesecond region.
 13. A structure comprising: a germanium layer above asemiconductor substrate in a first region of the semiconductorsubstrate; an optoelectronic device on the germanium layer in the firstregion, the optoelectronic device has a bottom cladding layer, an activeregion, and a top cladding layer, wherein the bottom cladding layer ison the germanium layer, the active region is on the bottom claddinglayer, and the top cladding layer is on the active region; a silicondevice on a silicon layer in a second region of the semiconductorsubstrate; and a waveguide embedded within an insulator layer, thewaveguide is in direct contact with a sidewall of the active region ofthe optoelectronic device, wherein both the top cladding layer and thebottom cladding layer are AlGaAs and the active region is GaAs.
 14. Thestructure according to claim 13, wherein the optoelectronic devicecomprises a III-V semiconductor material.
 15. The structure according toclaim 13, wherein the silicon device is a silicon complementarymetal-oxide-semiconductor (CMOS) device.
 16. The structure according toclaim 13, further comprising: a first contact, a second contact, and adevice contact, wherein the first contact is directly connected to thetop cladding layer, the second contact is directly connected to thebottom cladding layer, and the device contact is directly connected tothe silicon device.
 17. The structure according to claim 13, wherein theinsulator layer substantially covers both the optoelectronic device inthe first region and the silicon device in the second region.